package com.hmdp.utils;

import cn.hutool.core.lang.UUID;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;

import java.util.Collections;
import java.util.concurrent.TimeUnit;

public class SimpleRedisLock implements ILock{
    //不同的业务应该有不同的锁的名称
    private String name;
    private StringRedisTemplate stringRedisTemplate;

    public SimpleRedisLock(String name, StringRedisTemplate stringRedisTemplate) {
        this.name = name;
        this.stringRedisTemplate = stringRedisTemplate;
    }

    private static  final String KEY_PREFIX="lock:";
    private static  final String ID_PREFIX= UUID.randomUUID().toString(true)+"-";
    private static final DefaultRedisScript<Long> UNLOCK_SCRIPT;
    static {
        UNLOCK_SCRIPT=new DefaultRedisScript<>();
        UNLOCK_SCRIPT.setLocation(new ClassPathResource("unlock.lua"));
        UNLOCK_SCRIPT.setResultType(Long.class);
    }
    @Override
    public boolean tryLock(Long timeSec) {
        //获取当前线程标识
        String id = ID_PREFIX+Thread.currentThread().getId();
        //获取锁
        Boolean success = stringRedisTemplate.opsForValue()
                .setIfAbsent(KEY_PREFIX+name,id , timeSec, TimeUnit.SECONDS);
        //在自动拆箱的过程中防止空指针异常
        return Boolean.TRUE.equals(success);
    }
    @Override
    public void unlock() {
        //调用lua脚本
        //提前把脚本读取
        stringRedisTemplate.execute(UNLOCK_SCRIPT, Collections.singletonList(KEY_PREFIX+name),
                ID_PREFIX+Thread.currentThread().getId()
                );
    }

    /*@Override
    public void unlock() {
        //获取当前线程标识
        String id = ID_PREFIX+Thread.currentThread().getId();
        //获取锁中的标识
        String lockId = stringRedisTemplate.opsForValue().get(KEY_PREFIX+name);
        if (id.equals(lockId)){
            //释放锁
            stringRedisTemplate.delete(KEY_PREFIX+name);
        }
    }*/
}
